CN101949702A - Quick self-testing method for GNSS PVT quality by using MEMS accelerometer - Google Patents

Abstract

The invention provides a quick self-testing method for GNSS PVT quality by using an MEMS accelerometer. The method is characterized by comprising the following steps: differing a model of a previous accelerated speed calculated by GNSS and the model of the previous accelerated speed measured by the MEMS accelerometer according to current moment and previous moemnt to obtain the modular difference value of the accelerated speeds of the two models in a GNSS/MEMS INS composite system; and comparing the modular difference value with a preset dynamic range of the accelerated speed statistic characteristics of the composite system, deleting PVT value of the GNSS at current moment if the modular difference value exceeds the dynamic range, and maintaining the PVT value of the GNSS at the current moment to participate in composite filter if the modular difference value is in the dynamic range. The method has the advantages of small calculation capacity, easiness and practicality and strong real time, can quickly delete gross error, inhibit disadvantages of the gross error to the GNSS positioning, and complete quality self-testing on the PVT in the composite system.

Description

Use the GNSS PVT quality quick self-checking method of mems accelerometer

Technical field

The present invention relates to the satellite navigation technical field, particularly a kind of GNSS PVT quality quick self-checking method of using mems accelerometer, by the mould of GNSS and mems accelerometer gained acceleration is asked poor, and with predefined acceleration range relatively, the GNSS positioning result is judged and identification, and then reject the location rough error, realize the quick self-checking of PVT quality.Described MEMS is meant Micro Electro Mechanical System, described mems accelerometer is meant the accelerometer of making based on the MEMS technology, described GNSS refers to GPS (Global Position System), and described GNSS PVT is meant the locating information such as Position, Velocity and Time that GPS (Global Position System) obtains through positioning calculation.

Background technology

Micro-electromechanical system (MEMS) (Micro Electronic Mechanical System) is along with the development of SIC (semiconductor integrated circuit) Micrometer-Nanometer Processing Technology and ultraprecise Machining Technology grows up, and collection microsensor, actuator, signal Processing and control circuit, interface circuit, communicates by letter and the Micro Electro Mechanical System of power supply one.MEMS IMU is based on the Inertial Measurement Unit of MEMS technology, and it is integrated these two kinds of inertial sensors of silicon micro accerometer and silicon micro-gyroscope are used to measure the linear acceleration and the angular velocity of rotation of motion carrier.Owing to adopted micro electro mechanical system (MEMS) technology, the MEMS inertial sensor both inherited the conventional inertia sensor complete independence, strong security, do not have the characteristics such as electromagnetic interference (EMI) of signal, have again that size is little, in light weight, cost is low, power consumption is little, reliability is high, a wide dynamic range and be convenient to the incomparable advantages of conventional inertia sensor such as Installation and Debugging.Progressively replace traditional inertial sensor by its MEMS measuring unit that constitutes, make up the focus and emphasis that the integrated navigation system miniature, that cost is low has become the airmanship development.

GPS (Global Position System) GNSS (Global Navigation Satellite System) can for global user provide round-the-clock, continuously in real time, high accuracy three-dimensional position, three-dimensional velocity and time reference, have the not advantage of accumulation in time of error.But its navigation information updating speed is low, and is subject to the interference of external source and causes the interruption of positioning signal.Inertial navigation system INS (Inertial Navigation System), it then is the motion that utilizes inertial measuring unit (as accelerometer and gyroscope etc.) the measurement carrier that is installed on the carrier, the attitude and the positional information of output carrier, the INS system is autonomous fully, strong security, and maneuverability, but there is the problem of error run-up in time.Utilize MEMS INS and GNSS these two stronger non-similarity and complementarity, MEMS INS and GNSS are used in combination, then can give full play to both separately advantages, learn from other's strong points to offset one's weaknesses, make up the integrated navigation system of precision height, good reliability, finish long-range, the long-term navigation task of degree of precision.

The performance of integrated navigation system depends on the signal quality of GNSS.But because the GNSS signal is subject to influences such as satellite distribution, environment are blocked, multipath, undesired signal, cause PVT generation saltus step as a result and rough error occurs, its locator data reliabilty and availability is descended.When rough error is incorporated in the combined filter system as the external observation amount, will produce very big influence to system accuracy, filtering system is dispersed, influence the positioning result of navigation data.Therefore, not influenced by the problems referred to above, be necessary before combined filter, to carry out the detection of GNSS PVT quality, to reject the observed quantity rough error in order to guarantee the integrated navigation result.

Traditional Gross Error Detection method is to utilize the statistical property of the covariance matrix element in the GNSS wave filter, differentiate rough error whether occurred by statistical decision, and in GNSS/INS integrated kalman filter device, rough error point is carried out the filtering correction constantly by the method for weighting GNSS observation noise.But saltus step can take place along with the variation of rough error in conventional Kalman filtering result, causes vibration subsequently.Another kind of self-adaptation elimination of rough difference method based on Kalman filtering is to utilize the wave filter observation information to carry out the adaptive control of gain matrix, can realize judgement and rejecting to the dynamic data rough error, has avoided vibration, guarantees output smoothing.But above-described elimination of rough difference method all needs to utilize the statistical property of GNSS evaluated error and integrated navigation system residual sequence, the process complexity, and calculated amount is big, has certain limitation, and can't avoid the divergence problem of wave filter.

Summary of the invention

The present invention is directed to the defective and the deficiency that exist in the prior art, a kind of GNSS PVT quality quick self-checking method of using mems accelerometer is provided, compared with prior art, it is advantageous that the statistical property that need not to consider GNSS wave filter covariance, calculated amount is little, simple, real-time, can suppress the adverse effect that rough error causes the GNSS location.Described MEMS refers to Micro Electro Mechanical System, described mems accelerometer is meant the accelerometer of making based on the MEMS technology, described GNSS refers to GPS (Global Position System), and described GNSS PVT is meant the locating information such as Position, Velocity and Time that GPS (Global Position System) obtains through positioning calculation.

Technical scheme of the present invention is:

A kind of GNSS PVT quality quick self-checking method of using mems accelerometer, it is characterized in that, the mould of the previous moment acceleration that measures to the mould of being calculated the previous moment acceleration that draws by GNSS with by mems accelerometer according to current time and previous moment asks poor, obtains the mould difference of both acceleration in the GNSS/MEMS INS combined system; The dynamic range of described mould difference and predefined combined system acceleration statistical property is compared, if exceed dynamic range, then reject GNSS in the PVT of current time value, if do not exceed this scope, keep GNSS and participate in combined filter, need not to consider the statistical property of GNSS wave filter covariance in the PVT of current time value; Described MEMS refers to Micro Electro Mechanical System, described mems accelerometer is meant the accelerometer of making based on the MEMS technology, described GNSS refers to GPS (Global Position System), and described GNSS PVT is meant the locating information of the Position, Velocity and Time that GPS (Global Position System) process positioning calculation obtains; Described MEMS INS refers to the inertial navigation system based on the MEMS technology, it is integrated these two kinds of inertial sensors of silicon micro accerometer and silicon micro-gyroscope.

Described MEMS INS is made of three mutually orthogonal mems accelerometers and three mutually orthogonal MEMS gyroscopes, is respectively applied for linear acceleration and the angular velocity of measuring carrier.

Describedly calculate that by GNSS the mould of the previous moment acceleration draw is the mould of GNSS total acceleration, algorithm is as follows: establish GNSS current time T _kWith previous moment T _K-1Three direction e of output, n, the velocity amplitude of u (sky, northeast) is for Wei not V _{GNSS, i}(k) and V _{GNSS, i}(k-1), i=e wherein, n, u then calculates previous moment T _K-1The accekeration of three directions is:

$a_{\mathrm{GNSS},i}(k-1)=\frac{V_{\mathrm{GNSS},i}\left(k\right)-V_{\mathrm{GNSS},i}(k-1)}{T_k-T_{k-1}},i=e,n,u;$

By the derive mould of the total acceleration draw of GNSS be so

$a_{\mathrm{GNSS}}(k-1)=\sqrt{(a_{\mathrm{GNSS},e}^2(k-1)+a_{\mathrm{GNSS},n}^2(k-1)+a_{\mathrm{GNSS},u}^2(k-1))};$

The method of the mould of the described previous moment acceleration that is measured by mems accelerometer is as follows: use mems accelerometer, record at previous moment T _K-1(z) Shu Chu specific force value is respectively f to three orthogonal directionss for x, y _{IMU, x}(k-1), f _{IMU, y}(k-1), f _{IMU, z}(k-1), previous moment T then _K-1The mould of total specific force of mems accelerometer output is:

$f_{\mathrm{IMU}}(k-1)=\sqrt{(f_{\mathrm{IMU},x}^2(k-1)+f_{\mathrm{IMU},y}^2(k-1)+f_{\mathrm{IMU},z}^2(k-1))};$

The mould α of the total acceleration of measuring by mems accelerometer so _IMUCalculate by following formula:

α _IMU(k-1)=f _IMU(k-1)-g; Wherein, g is an acceleration of gravity.

The mould difference of both acceleration is the mould difference of GNSS and MEMS total acceleration in the described GNSS/MEMS INS combined system, is calculated by following formula:

δα＝α _IMU(k-1)-α _GNSS(k-1)。

To the mould difference of both acceleration in the described GNSS/MEMS INS combined system is that the mould difference of total acceleration is at current time T _kWith previous moment T _K-1Between integral and calculating:

$\mathrm{\δv}=\underset{T_{k-1}}{\overset{T_k}{\∫}}\mathrm{\δa}\·\mathrm{dT}$

Obtain the dynamic error of present speed; The dynamic error of present speed and the dynamic range of predefined combined system dynamic statistics characteristic are compared, if exceed dynamic range, then reject GNSS in the PVT of current time value,, keep GNSS and participate in combined filter in the PVT of current time value if do not exceed this scope.

The dynamic range of described predefined combined system acceleration statistical property comprises the dynamic range of each element in the GNSS/MEMS INS combined system noise matrix.

Adopt 6 σ statistical criteria that the dynamic range of each element in the difference of described acceleration mould and the GNSS/MEMS INS combined system noise matrix is compared.

Technique effect of the present invention:

Designed method of the present invention it is advantageous that the statistical property that need not to consider various filtering errors, and calculated amount is little, and is simple, real-time, and excluding gross error suppresses rough error to the influence that filtering causes fast, finishes the quality self-assessment of PVT in the combined system.

Description of drawings

Fig. 1 is the process flow diagram of the GNSS PVT quality quick self-checking method of use mems accelerometer.

Embodiment

Below in conjunction with accompanying drawing embodiments of the invention are described in further detail.

A kind of GNSS PVT quality quick self-checking method of using mems accelerometer, it is characterized in that, the mould of the previous moment acceleration that measures to the mould of being calculated the previous moment acceleration that draws by GNSS with by mems accelerometer according to current time and previous moment asks poor, obtains the mould difference of both acceleration in the GNSS/MEMS INS combined system; The dynamic range of described mould difference and predefined combined system acceleration statistical property is compared, if exceed dynamic range, then reject GNSS in the PVT of current time value, if do not exceed this scope, keep GNSS and participate in combined filter, need not to consider the statistical property of GNSS wave filter covariance in the PVT of current time value; Described MEMS refers to Micro Electro Mechanical System, described mems accelerometer is meant the accelerometer of making based on the MEMS technology, described GNSS refers to GPS (Global Position System), and described GNSS PVT is meant the locating information of the Position, Velocity and Time that GPS (Global Position System) process positioning calculation obtains; Described MEMS INS refers to the inertial navigation system based on the MEMS technology, it is integrated these two kinds of inertial sensors of silicon micro accerometer and silicon micro-gyroscope.

The Inertial Measurement Unit of MEMS INS is made of three mutually orthogonal mems accelerometers and three mutually orthogonal MEMS gyroscopes, is respectively applied for linear acceleration and the angular velocity of measuring carrier.

Referring to Fig. 1, use the flow process of the GNSS PVT quality quick self-checking method of mems accelerometer, may further comprise the steps: use mems accelerometer to measure the mould of a certain moment acceleration; Resolve the velocity amplitude of output according to GNSS PVT, calculate the mould of a certain moment acceleration; The mould of the total acceleration that calculates to the mould of the total acceleration that measured by mems accelerometer with by GNSS PVT asks poor, then the gained difference is carried out integration, obtains the speed dynamic error of GNSS PVT positioning result; The dynamic error value that above-mentioned integration is drawn and the dynamic range of predefined combined system acceleration statistical property compare, if exceed this scope, then reject this PVT value constantly, if do not exceed this scope, keep this PVT value participation combined filter constantly.

If T _kBe current time, use mems accelerometer, record at previous moment T _K-1(specific force value z) is respectively f to three orthogonal directionss for x, y _{IMU, x}(k-1), f _{IMU, y}(k-1), f _{IMU, z}(k-1), the mould that obtains total specific force of previous moment mems accelerometer output is

$f_{\mathrm{IMU}}(k-1)=\sqrt{(f_{\mathrm{IMU},x}^2(k-1)+f_{\mathrm{IMU},y}^2(k-1)+f_{\mathrm{IMU},z}^2(k-1))};$

The mould α of the total acceleration that estimates by MEMS so _IMUCan calculate by following formula

α _IMU(k-1)=f _IMU(k-1)-g; Wherein, g is an acceleration of gravity.

If GNSS resolves through PVT, obtain current T _kConstantly with previous moment T _K-1Three direction e of output, n, the velocity amplitude of u (sky, northeast) is for Wei not V _{GNSS, i}(k) and V _{GNSS, i}(k-1), i=e wherein, n, u, the accekeration that then calculates three directions of previous moment is

$a_{\mathrm{GNSS},i}(k-1)=\frac{V_{\mathrm{GNSS},i}\left(k\right)-V_{\mathrm{GNSS},i}(k-1)}{T_k-T_{k-1}},i=e,n,u$

By the derive mould of the total acceleration draw of GNSS be so

$a_{\mathrm{GNSS}}(k-1)=\sqrt{(a_{\mathrm{GNSS},e}^2(k-1)+a_{\mathrm{GNSS},n}^2(k-1)+a_{\mathrm{GNSS},u}^2(k-1))}$

The mould of the total acceleration that is measured by mems accelerometer and the mould of the total acceleration that GNSS calculates ask poor,

δα＝α _IMU(k-1)-α _GNSS(k-1)

Thereby the speed dynamic error is

$\mathrm{\δv}=\underset{T_{k-1}}{\overset{T_k}{\∫}}\mathrm{\δa}\·\mathrm{dT}.$

In GNSS/MEMS INS combined system, the system noise matrix has reacted the dynamic perfromance of combined system, set the wherein dynamic range of each element (being the speed random walk), adopt 6 σ statistical criteria that difference and this dynamic range of above-mentioned acceleration mould are compared, if exceed this scope, then reject this PVT value constantly, otherwise will keep this PVT value constantly, and participate in combined filter.

Should be pointed out that the above embodiment can make those skilled in the art more fully understand the invention, but do not limit the present invention in any way creation.Therefore, although this instructions and embodiment have been described in detail to the invention,, it will be appreciated by those skilled in the art that still and can make amendment or be equal to replacement the invention; And all do not break away from the technical scheme and the improvement thereof of the spirit and scope of the invention, and it all is encompassed in the middle of the protection domain of the invention patent.

Claims (7)

1. GNSS PVT quality quick self-checking method of using mems accelerometer, it is characterized in that, the mould of the previous moment acceleration that measures to the mould of being calculated the previous moment acceleration that draws by GNSS with by mems accelerometer according to current time and previous moment asks poor, obtains the mould difference of both acceleration in the GNSS/MEMS INS combined system; The dynamic range of described mould difference and predefined combined system acceleration statistical property is compared, if exceed dynamic range, then reject GNSS in the PVT of current time value, if do not exceed this scope, keep GNSS and participate in combined filter, need not to consider the statistical property of GNSS wave filter covariance in the PVT of current time value; Described MEMS refers to Micro Electro Mechanical System, described mems accelerometer is meant the accelerometer of making based on the MEMS technology, described GNSS refers to GPS (Global Position System), and described GNSS PVT is meant the locating information of the Position, Velocity and Time that GPS (Global Position System) process positioning calculation obtains; Described MEMS INS refers to the inertial navigation system based on the MEMS technology, it is integrated these two kinds of inertial sensors of silicon micro accerometer and silicon micro-gyroscope.

2. the GNSS PVT quality quick self-checking method of use mems accelerometer according to claim 1, it is characterized in that, described MEMS INS is made of three mutually orthogonal mems accelerometers and three mutually orthogonal MEMS gyroscopes, is respectively applied for linear acceleration and the angular velocity of measuring carrier.

3. the GNSS PVT quality quick self-checking method of use mems accelerometer according to claim 2 is characterized in that, describedly calculates that by GNSS the mould of the previous moment acceleration draw is the mould of GNSS total acceleration, and algorithm is as follows: establish GNSS current time T _kWith previous moment T _K-1Three direction e of output, n, the velocity amplitude of u (sky, northeast) is for Wei not V _{GNSS, i}(k) and V _{GNSS, i}(k-1), i=e wherein, n, u then calculates previous moment T _K-1The accekeration of three directions is:

$a_{\mathrm{GNSS},i}(k-1)=\frac{V_{\mathrm{GNSS},i}\left(k\right)-V_{\mathrm{GNSS},i}(k-1)}{T_k-T_{k-1}},i=e,n,u;$

By the derive mould of the total acceleration draw of GNSS be so

$a_{\mathrm{GNSS}}(k-1)=\sqrt{(a_{\mathrm{GNSS},e}^2(k-1)+a_{\mathrm{GNSS},n}^2(k-1)+a_{\mathrm{GNSS},u}^2(k-1))};$

The method of the mould of the described previous moment acceleration that is measured by mems accelerometer is as follows: use mems accelerometer, record at previous moment T _K-1(z) Shu Chu specific force value is respectively f to three orthogonal directionss for x, y _{IMU, x}(k-1), f _{IMU, y}(k-1), f _{IMU, z}(k-1), previous moment T then _K-1The mould of total specific force of mems accelerometer output is:

$f_{\mathrm{IMU}}(k-1)=\sqrt{(f_{\mathrm{IMU},x}^2(k-1)+f_{\mathrm{IMU},y}^2(k-1)+f_{\mathrm{IMU},z}^2(k-1))};$

The mould α of the total acceleration of measuring by mems accelerometer so _IMUCalculate by following formula:

α _IMU(k-1)=f _IMU(k-1)-g; Wherein, g is an acceleration of gravity.

4. the GNSS PVT quality quick self-checking method of use mems accelerometer according to claim 3, it is characterized in that, the mould difference of both acceleration is the mould difference of GNSS and MEMS total acceleration in the described GNSS/MEMS INS combined system, is calculated by following formula:

δα＝α _IMU(k-1)-α _GNSS(k-1)。

5. the GNSS PVT quality quick self-checking method of use mems accelerometer according to claim 4 is characterized in that, is that the mould difference of total acceleration is at current time T to the mould difference of both acceleration in the described GNSS/MEMS INS combined system _kWith previous moment T _K-1Between integral and calculating:

$\mathrm{\δv}=\underset{T_{k-1}}{\overset{T_k}{\∫}}\mathrm{\δa}\·\mathrm{dT}$

Obtain the dynamic error of present speed; The dynamic error of present speed and the dynamic range of predefined combined system dynamic statistics characteristic are compared, if exceed dynamic range, then reject GNSS in the PVT of current time value,, keep GNSS and participate in combined filter in the PVT of current time value if do not exceed this scope.

6. the GNSS PVT quality quick self-checking method of use mems accelerometer according to claim 4, it is characterized in that the dynamic range of described predefined combined system acceleration statistical property comprises the dynamic range of each element in the GNSS/MEMS INS combined system noise matrix.

7. the GNSS PVT quality quick self-checking method of use mems accelerometer according to claim 6, it is characterized in that, adopt 6 σ statistical criteria that the dynamic range of each element in the difference of described acceleration mould and the GNSS/MEMS INS combined system noise matrix is compared.

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